Most RAM that you will buy for desktop
systems these days is of the SIMM type. SIMM stands for Single Inline
Memory Module. They are small rectangular cards that can be inserted
into the system board. There are two main types of SIMM chip that you
Which type you use is determined by the
motherboard that you are using. If you are going for performance you
should try to use the DDR2 variety, as it is faster than DDR.
However, both types are very common, and DDR certainly delivers
adequate performance for most applications, even video games.
The two RAM types look very similar.
The only difference is the location of the small “notch”
in the middle of the pins. Figure 4-2 shows a DDR2 SIMM.
Figure 4-2: A DDR2 SIMM
DDR RAM looks very similar to DDR2.
Figure 4-3 shows a DDR SIMM.
Figure 4-3: A DDR SIMM
If you purchased the wrong type of RAM
for your motherboard, it will NOT fit. It is impossible to insert
DDR2 RAM into a DDR slot, or vise-versa. If the RAM will not fit, you
will need to either return the RAM or the motherboard.